Biogeochemistry of trace metals in the subarctic and Arctic oceans under a rapidly changing climate

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Microscopic marine plants and bacteria form the base of the ocean food web. The amount and chemical form of metals present in seawater can prevent plants and bacteria from growing either because they are scarce and essential nutrients like iron or zinc, or they are toxic when too much is available like lead or mercury. Metals can change how productive the marine food web can be by controlling which species, and how much of the microscopic plants and bacteria, can grow. Ultimately, metals then can control the oceans ability to take up greenhouse gases and slow climate change. Similarly, the health and sustainability of our fisheries can depend on the biological availability (bioavailability) of metal nutrients and toxins. Given that Canada is a country surrounded by three oceans this research has clear economic and cultural relevance to our citizens. *** My research group develops and uses highly sensitive analytical tools and approaches like mass spectrometry and electrochemistry to study metal chemistry in the ocean. The long-term goals of my research program are to understand the processes that control the distribution, chemical form and resulting bioavailability of trace metals, and how altered physical and chemical conditions in response to climate change are likely to impact these metal properties in the ocean. Recently, my research group has made significant progress towards these goals through the development and application of powerful analytical methods in both the field and the laboratory. We have focused on metals that control primary production and microbe community structure (e.g. Fe, Cu and Zn), serve as paleoceanographic tracers that provide important information regarding the oceans role is past climate change (e.g. Cd, Ag), or potentially toxic heavy metals that might negatively impact the marine ecosystem (Cu, Ag and Cd). Over the next 5 years my short term research objectives are to: 1) examine how changing temperature, ocean acidification and light where sea ice melts in high latitude ocean surface waters will impact biologically important metals; 2) unravel how much metals are either added or removed from the ocean near the continents; and 3) determine how decreasing oxygen levels in the ocean impact the relative distribution of metals.*** Our data will allow for better incorporation of metal chemistry in coupled atmosphere-ocean models designed to predict the response of marine systems in the Canadian subarctic and Arctic to regional warming, ocean acidification, ocean deoxygenation and changing sea ice and light regimes. In addition, a more thorough understanding of what controls the basin scale distribution of trace metals and their relationships with other ocean plant nutrients will aide in efforts to verify existing and develop new tools that can help us understand the oceans role in past climate change.**